How do I check if Oracle is up in Docker? - oracle

Question

As the title says: how do I check if Oracle is up in Docker? Now my app tries to create a Hibernate session and I'm getting
ERROR :
ORA-01033: ORACLE initialization or shutdown in progress
So I would like some kind of health check having url only. Is that possible? Thank you!

Answer 1

i'm using wnameless/oracle-xe-11g-r2 and this works for me
version: '3'
services:
db:
image: wnameless/oracle-xe-11g-r2
environment:
- ORACLE_ALLOW_REMOTE=true
ports:
- 49261:1521
volumes:
- ./0_init.sql:/docker-entrypoint-initdb.d/0_init.sql
healthcheck:
test: [ "CMD", "bash", "-c", "echo 'select 1 from dual;' | ORACLE_HOME=/u01/app/oracle/product/11.2.0/xe /u01/app/oracle/product/11.2.0/xe/bin/sqlplus -s USERNAME/PASSWORD#localhost"]
# docker inspect --format "{{json .State.Health }}" myproject_db_1
interval: 10s
timeout: 10s
retries: 60
myservice:
image: xxx
depends_on:
db:
condition: service_healthy

Answer 2

Using docker-compose.yml and Official Oracle docker images you can use checkDBStatus.sh script as a healthcheck. The script returns non-0 while db is in ORA-01033 state. Below is an example. Notice the combination of db's service healthcheck and tomcat's depends_on with service_healthy condition:
tomcat:
image: "tomcat:9.0"
depends_on:
oracle-db:
condition: service_healthy
links:
- oracle-db
services:
oracle-db:
build:
context: src/main/docker/oracle_db
dockerfile: Dockerfile.xe
mem_reservation: 2g
environment:
- ORACLE_PWD=oracle
volumes:
- oracle-data:/opt/oracle/oradata
healthcheck:
test: [ "CMD", "/opt/oracle/checkDBStatus.sh"]
interval: 2s
volumes:
oracle-data:

Answer 3

You can mimic tnsping in your Java app: How to do oracle TNSPING with java?
If you can't modify the app, tnsping can be called from a bash script - if you have Oracle client installed. If you don't, simply create a simple application from the link above and execute it in a script.

Answer 4

I've finished with a simple check for APEX:
while [[ "$(curl -s -o /dev/null -w ''%{http_code}'' db:8080/apex)" != "302" ]]; do sleep 5; done
302 is used because it redirects /apex to /apex/some_stuff. In my case db is the name of the container with Oracle:
version: '3'
services:
...
* other containers *
...
db:
image: some/image
ports:
- "8383:8080"
- "1521:1521"
Hope it helps someone!

Answer 5

If you are starting an oracle DB docker container within a jenkinsfile you may find this useful:
def waitForDbHealthy(containerName)
{
timeout(time: 4, unit: 'MINUTES')
{
def HEALTH_RESULT=""
while (! HEALTH_RESULT.toString().contains("healthy") )
{
echo "DB not yet healthy. going to sleep 10 sec."
sleep 10
HEALTH_RESULT=sh(returnStdout: true, script: "docker inspect --format='{{json .State.Health.Status}}' $containerName").trim()
echo "HEALTH_RESULT: $HEALTH_RESULT"
if ( HEALTH_RESULT.toString().contains("unhealthy") )
{
sh("docker logs $containerName")
echo "Going to throw IllegalStateException"
throw new IllegalStateException("Oracle DB switched to state unhealthy")
}
}
}
}
On my build server it tooks about 1 minute until the container is "healthy".
Be aware that oracle's TNS listener might not be ready yet. I found that an additional "sleep 60" (seconds) does the trick. Alternatively you can implement the java TNSPING as
Krzysztof Kaszkowiak pointed out in his answer.
Another note: Throwing an IllegalStateException is not allowed per default in Jenkinsfile's groovy. Your Jenkins administrator must explicitely accept it (Jenkins/Manage Jenkins/In-process Script Approval).
Jenkins 2.249.2
Docker Version: 19.03.8
Oracle docker image: based on store/oracle/database-enterprise:12.2.0.1-slim